• 한국정보전자통신기술학회논문지
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• 제4권1호
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• pp.61-67
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• 2011

YAG:Ce 형광제 제조에 있어서 공침(co-precipitation) 후 n-butanol 공비증류(azeotropic distillation)시 HMDS(hexadimethyldisilazane)를 첨가하였을 때, 형광체가 광학특성에 미치는 영향에 관하여 연구하였다. 물과 유기용제에 의한 공비증류 시 유기용제의 분자량이 크면 표면의 수소결합이 유기용제로 치환됨으로서 표면장력을 감소시켜 분체의 원형화(conglobation)와 응집(agglomerate)을 감소시키므로 유기용제로 n-butanol보다 분자량이 큰 HMDS을 첨가하였다. N-butanol 만을 사용한 형광체가 HMDS를 첨가한 것 보다 응집(agglomerate)되는 현상이 감소하였으며 우수한 광학적 특성을 나타내었다.

• 대한금속재료학회지
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• 제50권6호
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• pp.439-443
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• 2012

YAG:Ce phosphor were prepared in a self-propagating high-temperature synthesis (SHS) using a $1.5Y_2O_3+2.5Al_2O_3+0.116CeO_2+3.0KClO_3+kCO(NH_2)_2+m(C_2F_4)_n$ precursor mixture. The heat for the combustion propagation was provided by the reaction of a $KClO_3+CO(NH_2)_2+(C_2F_4)n$ mixture. Pure-phase YAG phosphor was synthesized at the combustion temperature of $1210^{\circ}C$ from k=3.6 mole and m=0.3 mole. The as-prepared YAG:Ce phosphor had a particle size of $2-10{\mu}m$. The addition of Teflon to the precursor mixture increased the YAG particle size and its luminescent intensity. The emission peak of the YAG phosphor was blue-shifted with an increase of Teflon concentration.

• 한국결정성장학회지
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• 제27권1호
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• pp.18-21
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• 2017

본 연구에서는 homogeneous precipitation method를 통하여 구형의 단분산(monodispersed) YAG : $Ce^{3+}$를 합성했다. 단분산 YAG : $Ce^{3+}$의 전구체를 합성하는 과정에서 aluminum ion들이 먼저 석출되어 aluminum 화합물을 형성하고 후에 yttrium 화합물들이 aluminum 화합물들의 표면에서 석출된다. 합성된 전구체를 파우더형태로 얻기 위해 건조과정을 거치는데, oven에서 건조했을 때 보다 동결건조기에서 건조했을 때 비교적 구형의 단분산 YAG : $Ce^{3+}$ 입자를 얻을 수 있었다. 하소 과정에서 공정을 진행하는 온도로서 $1100^{\circ}C$와 $1200^{\circ}C$를 비교해 보았다. 실험 결과 $1200^{\circ}C$의 온도로 상압에서 6시간 동안의 하소 과정을 진행하였을 때 400~500 nm 입자크기를 가진 단분산된 구형의 나노 YAG : $Ce^{3+}$ 입자가 합성되었다.

• 한국광학회지
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• 제24권3호
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• pp.135-142
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• 2013

본 논문에서는 YAG:Ce와 $(Sr,Ba)_2SiO4:Eu$ 등 두 종류의 형광체를 사용하여 백색 LED를 제작하고 온도변화에 따라 각각의 백색 LED의 발광 특성이 어떻게 변하는지 조사하였다. 상온에서 $80^{\circ}C$ 사이의 구간에서 측정된 두 백색 LED의 발광 스펙트럼을 분석하기 위해 asymmetric double sigmoidal 함수를 활용하였다. 이 함수를 백색 LED의 청색 발광 및 황색 발광 피크에 적용해서 각 피크의 중심파장과 진폭, 반치폭 및 비대칭성을 온도의 함수로 구하였다. 그 결과 온도가 증가할수록 청색 피크의 중심파장이 장파장 쪽으로 천이되고 황색피크의 중심파장이 단파장 쪽으로 천이되며 비대칭성 또한 증가한다는 것을 확인할 수 있었다. 이러한 결과는 두 백색 LED의 색도변화에 반영되었는데, 실리케이트계 형광체 기반 LED의 색도 변화가 더 큼을 알 수 있었다. 발광효율 역시 온도가 증가할수록 크게 떨어지는 것을 볼 수 있었는데 YAG 형광체 기반 LED의 발광효율 저하 폭이 더 적음을 확인하였다. 이상의 결과는 YAG 형광체 기반 백색 LED가 실리케이트계 형광체 기반 LED에 비해 색도안정성, 발광효율, 연색지수 측면에서 더 뛰어나다는 것을 의미한다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.142.2-142
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• 2003

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.489-490
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• 2006

The Ce-doped YAG(Yttrium Aluminum Garnet, $Y_3Al_5O_{12}$) phosphor powders were synthesized by Sol-gel method. The luminescence, formation process and structure of phosphor powders were investigated by means of XRD, SEM and PL. The XRD patterns show that YAG phase can form through sintering at $1000^{\circ}C$ for 2h. This temperature is much lower than that required to synthesize YAG phase via the conventional solid state reaction method. There were no intermediate phases such as YAP(Yttrium Aluminum Perovskite, $YAlO_3$) and YAM(Yttrium Aluminum Monoclinic, $Y_4Al_2O_9$) observed in the sintering process. The powders absorbed excitation energy in the range 410~510nm. Also, the crystalline YAG:Ce showed broad emission peaks in the range 480~600nm and had maximum intensity at 528nm.

• 한국세라믹학회지
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• 제51권5호
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• pp.424-429
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• 2014

YAG:$Ce^{3+}$ phosphor powders were synthesized using $Al(OH)_3$ seeds by means of a PVA-polymer-solution route. Various types of PVA with different molecular weights (different polymerization) were used. All dried precursor gels were calcined at $500^{\circ}C$ and then heated at $1500^{\circ}C$ in a mix of nitrogen and hydrogen gases. The final powders were characterized via XRD, SEM, PSA, PL, and PKG analyses. The phosphor properties and morphologies of the synthesized powders were dependent on the PVA type. As the molecular weight of the PVA was increased, the particle size gradually decreased with agglomeration, and the luminous intensity of the phosphor increased. However, the phosphor powder prepared from the PVA exhibiting very high molecular weight, showed a 531 nm (blue) shift from the 541 nm (yellow) wavelength of the YAG:$Ce^{3+}$ phosphor. Finally, the synthesized YAG:$Ce^{3+}$ phosphor powder prepared from the PVA with 89,000 - 98,000 molecular weight showed phosphor properties similar to those of a commercial phosphor powder, but without a post-treatment process.

• 한국분말재료학회지
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• 제30권5호
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• pp.424-430
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• 2023

YAG phosphor powders were fabricated by the atmospheric plasma spraying method with the spray-dried spherical YAG precursor. The YAG precursor slurry for the spray drying process was prepared by the PVA solution chemical processing utilizing a domestic easy-sintered aluminum oxide (Al₂O₃) powder as a seed. The homogenous and viscous slurry resulted in dense granules, not hollow or porous particles. The synthesized phosphor powders demonstrated a stable YAG phase, and excellent fluorescence properties of approximately 115% compared with commercial YAG:Ce³⁺ powder. The microstructure of the phosphor powder had a perfect spherical shape and an average particle size of approx imately 30 ㎛. As a result of the PKG test of the YAG phosphor powder, the synthesized phosphor powders exhibited an outstanding luminous intensity, and a peak wavelength was observed at 531 nm.

• 한국분말재료학회지
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• 제20권1호
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• pp.37-42
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• 2013

$YAG:Ce^{3+}$ phosphor powders were synthesized using a $Al_2O_3$ seed (average particle size: 5 ${\mu}m$) by the polymer solution route. PVA solution was added to the sol precursors consisting of the seed powder and metal nitrate salts for homogeneous mixing in atomic scale. All dried precursor gels were calcined at $500^{\circ}C$ and then heated at $1400^{\circ}C{\sim}1500^{\circ}C$ in $N_2/H_2$ atmosphere. The final powders were characterized by using XRD, SEM, PSA, PL and PKG test. All synthesized powders were crystallized to YAG phase without intermediate phases of YAM or YAP. The phosphor properties and morphologies of the synthesized powders were strongly dependent on the PVA content. Finally, the synthesized $YAG:Ce^{3+}$ phosphor powder heated at $1500^{\circ}C$, which is prepared from 12:1 PVA content and has an average particle size of 15 ${\mu}m$, showed similar phosphor properties to a commercial phosphor powder.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.441-442
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• 2008

For this study, Yttrium aluminum garnet (YAG) particles co-doped with $Ce^{3+}$ and $Eu^{3+}$ were prepared via the combustion process using the 1:1 ratio of metal ions to reagents. The characteristics of the synthesized nano powder were investigated by means of X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and photoluminescence (PL). The various YAG peaks, with the (420) main peak, appeared at all Eu concentrationin XRD patterns. The YAG phase crystallized with results that are in good agreement with the JCPDS diffraction file 33-0040. The SEM image showed that the resulting YAG:Ce,Eu powders had uniform sizes and good homogeneity. The grain size was about 50nm. The photoluminescence spectra of the YAG:Ce,Eu nanoparticles were investigated to determine the energy level of electron transition related to luminescence processes. It was composed a broad band of $Ce^{3+}$ activator into the weak line peak of $Eu^{3+}$ in YAG host. The PL intensity of $Ce^{3+}$ has the wavelengths of 480-650 nm and The PL intensity of $Eu^{3+}$ has main peak at 590nm.